This invention relates generally to semiconductor integrated circuit structures and manufacturing methods and more particularly to semiconductor integrated circuit structures having multiple layer metal conductors and manufacturing methods therefor.
As is known in the art, semiconductor integrated circuits have been formed by depositing metal on the surface of an oxide mask and through apertures formed in such mask to selected regions of active elements formed as a single crystal body. One such metal is aluminum and the resulting metallization forms a first metal interconnecting system. A second metal interconnecting system is formed on a second oxide mask which is deposited over the first metal interconnecting system, and through apertures formed in such second oxide mask to selected conductors of the first metal interconnecting system. Because aluminum is a reactive metal, the use of such metal as the second interconnecting metal results in compounds, such as oxides, being formed between the aluminum-aluminum metal interconnecting layers, thereby preventing complete, reproducible ohmic via contacts from being formed between such first and second metal interconnecting systems.